package leetCode;

public class Q21 {
    public class ListNode {
        int val;
        ListNode next;

        ListNode() {
        }

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }

    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        ListNode head = new ListNode();
        ListNode cur = head;
        while (list1 != null && list2 != null) {
            if(list1.val<list2.val){
                cur.next = list1;
                list1 = list1.next;
            }else {
                cur.next = list2;
                list2 = list2.next;
            }
            cur = cur.next;
        }
        if(list1!=null) cur.next = list1;
        if(list2!=null) cur.next = list2;

        return head.next;
    }
}
